1.It is a fact that … 事实是…
It is a fact that the earth goes around the sun.
2.It is said that … 据说…
It is said that the film is on tomorrow.
3.It is generally considered that … 人们普遍认为…
It is generally considered that Beijing will be a cosmopolis.
4.It is necessary that … 有必要…
It is necessary that one should wash hands before meal.
5.It is likely that … 很可能…
It is likely that he will succeed.
6.It is questionable that … 成问题的是…
It is questionable that the earth is becoming hotter.
7.It follows that … 由此可见…
It follows that you'd better bring the umbrella with you.
8.It may be that … 可能…
It may be that it will rain tomorrow